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Ding S, Fontaine T, Serex M, Sá Dos Reis C. Strategies enhancing the patient experience in mammography: A scoping review. Radiography (Lond) 2024; 30:340-352. [PMID: 38141428 DOI: 10.1016/j.radi.2023.11.016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2023] [Revised: 11/10/2023] [Accepted: 11/14/2023] [Indexed: 12/25/2023]
Abstract
INTRODUCTION A positive experience in mammography is essential for increasing patient attendance and reattendance at these examinations, whether conducted for diagnostic or screening purposes. Mammograms indeed facilitate early disease detection, enhance the potential for cure, and consequently reduce breast cancer mortality. The main objective of this review was to identify and map the strategies aiming to improve the patient experience in diagnostic and screening mammography. METHODS This scoping review was performed following the JBI methodology and the Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension for Scoping Reviews (PRISMA-ScR). Searches were performed through databases of MEDLINE, Embase.com, CINAHL, APA PsycINFO, Cochrane Central Register of Controlled Trials, Web of Science, ProQuest Dissertation and Theses, and three clinical trial registries. This review considered studies evaluating the effect of interventions, occurring within the mammography department, on the patient experience. RESULTS The literature search yielded 8113 citations of which 60, matching the inclusion criteria, were included. The strategies were classified into eight categories. The most represented one was breast compression and positioning, followed by relaxation techniques and analgesic care, communication and information, screening equipment, examination procedures, patient-related factors, physical environment, and finally staff characteristics. The studied outcomes related to patient experience were mainly pain, anxiety, comfort, and satisfaction. Other types of outcomes were also considered in the studies such as image quality, technical parameters, or radiation dose. Most studies were conducted by radiographers, on female patients, and none mentioned the inclusion of male or transgender patients. CONCLUSION This review outlined a diversity of strategies to improve patient experience, although technique-based interventions were predominant. Further research is warranted, notably on psychological strategies, and on men and transgender people. IMPLICATIONS FOR PRACTICE This scoping review provides guidance to healthcare providers and services for better patient/client-centered care.
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Affiliation(s)
- S Ding
- Department of Radiologic Medical Imaging Technology, School of Health Sciences (HESAV), HES-SO University of Applied Sciences and Arts Western, Switzerland; BEST JBI Centre of Excellence, Switzerland.
| | - T Fontaine
- Department of Radiologic Medical Imaging Technology, School of Health Sciences (HESAV), HES-SO University of Applied Sciences and Arts Western, Switzerland
| | - M Serex
- Library, School of Health Sciences (HESAV), HES-SO University of Applied Sciences and Arts Western, Switzerland
| | - C Sá Dos Reis
- Department of Radiologic Medical Imaging Technology, School of Health Sciences (HESAV), HES-SO University of Applied Sciences and Arts Western, Switzerland
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Barbari C, Fontaine T, Parajuli P, Lamichhane N, Jakubski S, Lamichhane P, Deshmukh RR. Immunotherapies and Combination Strategies for Immuno-Oncology. Int J Mol Sci 2020; 21:E5009. [PMID: 32679922 PMCID: PMC7404041 DOI: 10.3390/ijms21145009] [Citation(s) in RCA: 43] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2020] [Revised: 07/10/2020] [Accepted: 07/13/2020] [Indexed: 12/15/2022] Open
Abstract
The advent of novel immunotherapies in the treatment of cancers has dramatically changed the landscape of the oncology field. Recent developments in checkpoint inhibition therapies, tumor-infiltrating lymphocyte therapies, chimeric antigen receptor T cell therapies, and cancer vaccines have shown immense promise for significant advancements in cancer treatments. Immunotherapies act on distinct steps of immune response to augment the body's natural ability to recognize, target, and destroy cancerous cells. Combination treatments with immunotherapies and other modalities intend to activate immune response, decrease immunosuppression, and target signaling and resistance pathways to offer a more durable, long-lasting treatment compared to traditional therapies and immunotherapies as monotherapies for cancers. This review aims to briefly describe the rationale, mechanisms of action, and clinical efficacy of common immunotherapies and highlight promising combination strategies currently approved or under clinical development. Additionally, we will discuss the benefits and limitations of these immunotherapy approaches as monotherapies as well as in combination with other treatments.
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Affiliation(s)
- Cody Barbari
- OMS Students, School of Osteopathic Medicine, Lake Erie College of Osteopathic Medicine (LECOM), 5000 Lakewood Ranch Blvd, Bradenton, FL 34211, USA; (C.B.); (T.F.)
| | - Tyler Fontaine
- OMS Students, School of Osteopathic Medicine, Lake Erie College of Osteopathic Medicine (LECOM), 5000 Lakewood Ranch Blvd, Bradenton, FL 34211, USA; (C.B.); (T.F.)
| | - Priyanka Parajuli
- Department of Internal Medicine, Southern Illinois University, Springfield, IL 62702, USA;
| | - Narottam Lamichhane
- Department of Radiation Oncology, University of Maryland, School of Medicine, Baltimore, MD 21201, USA;
| | - Silvia Jakubski
- Department of Biostatistics, University of Florida, Gainesville, FL 32611, USA;
| | - Purushottam Lamichhane
- School of Dental Medicine, Lake Erie College of Osteopathic Medicine (LECOM), 4800 Lakewood Ranch Blvd, Bradenton, FL 34211, USA
| | - Rahul R. Deshmukh
- School of Pharmacy, Lake Erie College of Osteopathic Medicine (LECOM), 5000 Lakewood Ranch Blvd, Bradenton, FL 34211, USA
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Baudouin A, Fontaine T, Carnal I, Gerome P, Lablanche C, Girard P, Dussart C. [Care pathway for high urinary tract infection: an update in an emergency department of a French military hospital]. J Pharm Belg 2016:18-25. [PMID: 30281227] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Objectives Assessing the impact of professional practices on a patient's course is an interesting way to optimize health care pathway. The aim of our study is to update and evaluate the compliance to the recommendations of the Societe de Pathologie Infectieuse de Langue Francaise with regards to professional practices and the route of patients admitted to the emergency department of a French military hospital for high urinary tract infection. Patients and methods A retrospective study was carried out on patients admitted to the emergency department and treated for high urinary tract infection from January 1st, 2015 to April 30th, 2015. Clinical and administrative data, medical exams, and antibiotic prescriptions were extracted from computerized patient medical files and from emergency medical files. Results Out of 91 medical cares, 57% were compliant with the recommendations. For 60% of the patients, blood cultures were not argued and in 70% of cases, imaging wasn't justified. Antibiotic prescriptions were not compliant in 31% of cases, mostly due to long prescription durations. Two third of patients received outpatient care. All hospitalizations were argued. Conclusions Drawing up a caring protocol, regularly raising awareness to the good use of antibiotics, as well as reinforcing a cross disciplinary approach will allow optimizing health care pathways for patients coming to the emergency department with high urinary tract infection.
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Jawhara S, Choteau L, Dubuquoy L, Vanderkerkove P, Fontaine T, Guerardel Y, Sendid B, Jouault T, Poulain D. Analyse expérimentale de la colonisation intestinale par Candida albicans et modulation de la réponse immuno-inflammatoire de l’hôte. J Mycol Med 2013. [DOI: 10.1016/j.mycmed.2013.07.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Spada R, Stella G, Calabrese S, Bosco P, Anello G, Gueant-Rodriguez RM, Romano A, Benamghar L, Fontaine T, Gueant JL. Prevalence of dementia in a mountainous village of Sicily. J Neurol Sci 2009. [DOI: 10.1016/j.jns.2009.02.264] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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Simenel C, Coddeville B, Delepierre M, Latge JP, Fontaine T. Glycosylinositolphosphoceramides in Aspergillus Fumigatus. Glycobiology 2007; 18:84-96. [DOI: 10.1093/glycob/cwm122] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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Mouyna I, Sarfati J, Recco P, Fontaine T, Henrissat B, Latge JP. Molecular characterization of a cell wall-associated ß(1-3)endoglucanase of Aspergillus fumigatus. Med Mycol 2002. [DOI: 10.1080/714031140] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022] Open
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Mouyna I, Sarfati J, Recco P, Fontaine T, Henrissatz B, Latge JP. Molecular characterization of a cell wall-associated beta(1-3)endoglucanase of Aspergillus fumigatus. Med Mycol 2002; 40:455-64. [PMID: 12462524 DOI: 10.1080/mmy.40.5.455.464] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022] Open
Abstract
A 74 kDa beta(1-3)endoglucanase of Aspergillus fumigatus was recently isolated from a cell wall autolysate and biochemically characterized. In this study, we report the cloning and the disruption of the ENGL1 gene encoding this beta(1-3)endoglucanase. ENGL1 contains an open reading frame of 2181 bp encoding a polypeptide of 727 amino acids. Sequence analysis showed that ENGL1 is the first characterized member of a new family of beta(1-3)glucanases. Disruption of ENGL1, however, did not lead to a phenotype distinct from the parental strain, indicating that this cell wall-associated beta(1-3)endoglucanase does not play an essential role in constitutive cell growth.
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Affiliation(s)
- I Mouyna
- Institut Pasteur, Unité des Aspergillus, 25 rue du Docteur Roux 75724 Paris Cedex 15, France.
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Abstract
A new allergen from horse dander, Equ c 5 has been purified. Its biochemical and biophysical properties have been characterized and compared with those of Equ c 1, Equ c 2 and Equ c 4. Their molecular masses, determined by mass spectrometry, were 22 kDa for Equ c 1, 16 kDa for Equ c 2, 18.7 kDa for Equ c 4 and 16.7 kDa for Equ c 5. Their pI values were between 3.8 and 5.25. Equ c 2 and Equ c 5 are not glycosylated, while Equ c 4 contains a tri-antennary tri-sialylated N-linked glycan. Linkages of terminal N-acetylneuraminic acid to galactose were: alpha-(2-->6) in Equ c 4, and both alpha-(2-->3) and alpha-(2-->6) in Equ c 1. Oligosaccharide portions of Equ c 1 or Equ c 4 were barely involved in IgE-immunoreactivity. Partial N-terminal sequence of Equ c 4 shares a significant sequence homology with the rat submandibular gland protein A. No matching was found for two internal peptides of Equ c 5. Surfactant properties of horse allergens as well as other proteins were investigated. In contrast to Equ c 2 and Equ c 3, solutions of Equ c 1, Equ c 4 and Equ c 5 significantly lowered the surface tension. Relationship between a property such as this, involving oriented hydrophobic patches of a molecule and allergenicity, is addressed.
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Fontaine T, Simenel C, Dubreucq G, Adam O, Delepierre M, Lemoine J, Vorgias CE, Diaquin M, Latgé JP. Molecular organization of the alkali-insoluble fraction of Aspergillus fumigatus cell wall. J Biol Chem 2000; 275:27594-607. [PMID: 10869365 DOI: 10.1074/jbc.m909975199] [Citation(s) in RCA: 287] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Physical and biological properties of the fungal cell wall are determined by the composition and arrangement of the structural polysaccharides. Cell wall polymers of fungi are classically divided into two groups depending on their solubility in hot alkali. We have analyzed the alkali-insoluble fraction of the Aspergillus fumigatus cell wall, which is the fraction believed to be responsible for fungal cell wall rigidity. Using enzymatic digestions with recombinant endo-beta-1,3-glucanase and chitinase, fractionation by gel filtration, affinity chromatography with immobilized lectins, and high performance liquid chromatography, several fractions that contained specific interpolysaccharide covalent linkages were isolated. Unique features of the A. fumigatus cell wall are (i) the absence of beta-1,6-glucan and (ii) the presence of a linear beta-1, 3/1,4-glucan, never previously described in fungi. Galactomannan, chitin, and beta-1,3-glucan were also found in the alkali-insoluble fraction. The beta-1,3-glucan is a branched polymer with 4% of beta-1,6 branch points. Chitin, galactomannan, and the linear beta-1, 3/1,4-glucan were covalently linked to the nonreducing end of beta-1, 3-glucan side chains. As in Saccharomyces cerevisiae, chitin was linked via a beta-1,4 linkage to beta-1,3-glucan. The data obtained suggested that the branching of beta-1,3-glucan is an early event in the construction of the cell wall, resulting in an increase of potential acceptor sites for chitin, galactomannan, and the linear beta-1,3/1,4-glucan.
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Affiliation(s)
- T Fontaine
- Laboratoire des Aspergillus, Institut Pasteur, 25 rue du Docteur Roux, 75724 Paris cedex 15, France.
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Mesnage S, Fontaine T, Mignot T, Delepierre M, Mock M, Fouet A. Bacterial SLH domain proteins are non-covalently anchored to the cell surface via a conserved mechanism involving wall polysaccharide pyruvylation. EMBO J 2000; 19:4473-84. [PMID: 10970841 PMCID: PMC302060 DOI: 10.1093/emboj/19.17.4473] [Citation(s) in RCA: 270] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Several bacterial proteins are non-covalently anchored to the cell surface via an S-layer homology (SLH) domain. Previous studies have suggested that this cell surface display mechanism involves a non-covalent interaction between the SLH domain and peptidoglycan-associated polymers. Here we report the characterization of a two-gene operon, csaAB, for cell surface anchoring, in Bacillus anthracis. Its distal open reading frame (csaB) is required for the retention of SLH-containing proteins on the cell wall. Biochemical analysis of cell wall components showed that CsaB was involved in the addition of a pyruvyl group to a peptidoglycan-associated polysaccharide fraction, and that this modification was necessary for binding of the SLH domain. The csaAB operon is present in several bacterial species that synthesize SLH-containing proteins. This observation and the presence of pyruvate in the cell wall of the corresponding bacteria suggest that the mechanism described in this study is widespread among bacteria.
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Affiliation(s)
- S Mesnage
- Toxines et Pathogénie Bactériennes (URA 1858, CNRS), Institut Pasteur, 28 rue du Dr Roux, 75724 Paris, cédex 15, France
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Mouyna I, Fontaine T, Vai M, Monod M, Fonzi WA, Diaquin M, Popolo L, Hartland RP, Latgé JP. Glycosylphosphatidylinositol-anchored glucanosyltransferases play an active role in the biosynthesis of the fungal cell wall. J Biol Chem 2000; 275:14882-9. [PMID: 10809732 DOI: 10.1074/jbc.275.20.14882] [Citation(s) in RCA: 283] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
A novel 1,3-beta-glucanosyltransferase isolated from the cell wall of Aspergillus fumigatus was recently characterized. This enzyme splits internally a 1,3-beta-glucan molecule and transfers the newly generated reducing end to the non-reducing end of another 1, 3-beta-glucan molecule forming a 1,3-beta linkage, resulting in the elongation of 1,3-beta-glucan chains. The GEL1 gene encoding this enzyme was cloned and sequenced. The predicted amino acid sequence of Gel1p was homologous to several yeast protein families encoded by GAS of Saccharomyces cerevisiae, PHR of Candida albicans, and EPD of Candida maltosa. Although the expression of these genes is required for correct morphogenesis in yeast, the biochemical function of the encoded proteins was unknown. The biochemical assays performed on purified recombinant Gas1p, Phr1p, and Phr2p showed that these proteins have a 1,3-beta-glucanosyltransferase activity similar to that of Gel1p. Biochemical data and sequence analysis have shown that Gel1p is attached to the membrane through a glycosylphosphatidylinositol in a similar manner as the yeast homologous proteins. The activity has been also detected in membrane preparations, showing that this 1,3-beta-glucanosyltransferase is indeed active in vivo. Our results show that transglycosidases anchored to the plasma membrane via glycosylphosphatidylinositols can play an active role in fungal cell wall synthesis.
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Affiliation(s)
- I Mouyna
- Institut Pasteur, Laboratoire des Aspergillus, 25 Rue du Docteur Roux, 75724 Paris, Cedex 15, France.
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Mouyna I, Monod M, Fontaine T, Henrissat B, Léchenne B, Latgé JP. Identification of the catalytic residues of the first family of beta(1-3)glucanosyltransferases identified in fungi. Biochem J 2000; 347 Pt 3:741-7. [PMID: 10769178 PMCID: PMC1221011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/16/2023]
Abstract
A new family of glycosylphosphatidylinositol-anchored beta(1-3)glucanosyltransferases (Gelp), recently identified and characterized in the filamentous fungus Aspergillus fumigatus, showed functional similarity to the Gas/Phr/Epd protein families, which are involved in yeast morphogenesis. Sequence comparisons and hydrophobic cluster analysis (HCA) showed that all the Gas/Phr/Epd/Gel proteins belong to a new family of glycosylhydrolases, family 72. We confirmed by site-directed mutagenesis and biochemical analysis that the two conserved glutamate residues (the putative catalytic residues of this family, as determined by HCA) are involved in the active site of this family of glycosylhydrolases.
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Affiliation(s)
- I Mouyna
- Institut Pasteur, Laboratoire des Aspergillus, 25 rue du Docteur Roux, 75724 Paris Cédex 15, France.
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d'Enfert C, Bonini BM, Zapella PD, Fontaine T, da Silva AM, Terenzi HF. Neutral trehalases catalyse intracellular trehalose breakdown in the filamentous fungi Aspergillus nidulans and Neurospora crassa. Mol Microbiol 1999; 32:471-83. [PMID: 10320571 DOI: 10.1046/j.1365-2958.1999.01327.x] [Citation(s) in RCA: 88] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
A cAMP-activatable Ca2+-dependent neutral trehalase was identified in germinating conidia of Aspergillus nidulans and Neurospora crassa. Using a PCR approach, A. nidulans and N. crassa genes encoding homologues of the neutral trehalases found in several yeasts were cloned and sequenced. Disruption of the AntreB gene encoding A. nidulans neutral trehalase revealed that it is responsible for intracellular trehalose mobilization at the onset of conidial germination, and that this phenomenon is partially involved in the transient accumulation of glycerol in the germinating conidia. Although trehalose mobilization is not essential for the completion of spore germination and filamentous growth in A. nidulans, it is required to achieve wild-type germination rates under carbon limitation, suggesting that intracellular trehalose can partially contribute the energy requirements of spore germination. Furthermore, it was shown that trehalose accumulation in A. nidulans can protect germinating conidia against an otherwise lethal heat shock. Because transcription of the treB genes is not increased after a heat shock but induced upon heat shock recovery, it is proposed that, in filamentous fungi, mobilization of trehalose during the return to appropriate growth is promoted by transcriptional and post-translational regulatory mechanisms, in particular cAMP-dependent protein kinase-mediated phosphorylation.
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Affiliation(s)
- C d'Enfert
- Laboratoire des Aspergillus, Institut Pasteur, 25 rue du Docteur Roux, 75724 Paris Cedex 15, France.
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Fontaine T, Hartland RP, Diaquin M, Simenel C, Latgé JP. Differential patterns of activity displayed by two exo-beta-1,3-glucanases associated with the Aspergillus fumigatus cell wall. J Bacteriol 1997; 179:3154-63. [PMID: 9150209 PMCID: PMC179092 DOI: 10.1128/jb.179.10.3154-3163.1997] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Two exo-beta-1,3-glucanases (herein designated exoG-I and exoG-II) were isolated from the cell wall autolysate of the filamentous fungus Aspergillus fumigatus and purified by ion-exchange, hydrophobic-interaction, and gel filtration chromatographies. Molecular masses estimated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and gel filtration chromatography were 82 kDa for the monomeric exoG-I and 230 kDa for the dimeric exoG-II. exoG-I and exoG-II were glycosylated, and N glycans accounted, respectively, for 2 and 44 kDa. Their pH optimum is 5.0. Their optimum temperatures are 55 degrees C for exoG-I and 65 degrees C for exoG-II. By a sensitive colorimetric method and high-performance anion-exchange chromatography for product analysis, two patterns of exo-beta-1,3-glucanase activities were found. The 230-kDa exoG-II enzyme acts on p-nitrophenyl-beta-D-glucoside, beta-1,6-glucan, and beta-1,3-glucan. This activity, which retains the anomeric configuration of glucose released, presented a multichain pattern of attack of the glucan chains and a decrease in the maximum initial velocity (Vm) with the increasing size of the substrate. In contrast, the 82-kDa exoG-I, which inverts the anomeric configuration of the glucose released, hydrolyzed exclusively the beta-1,3-glucan chain with a minimal substrate size of 4 glucose residues. This enzyme presented a repetitive-attack pattern, characterized by an increase in Vm with an increase in substrate size and by a degradation of the glucan chain until it reached laminaritetraose, the limit substrate size. The 82-kDa exoG-I and 230-kDa exoG-II enzymes correspond to a beta-1,3-glucan-glucohydrolase (EC 3.2.1.58) and to a beta-D-glucoside-glucohydrolase (EC 3.2.1.21), respectively. The occurrence and functions of these two classes of exo-beta-1,3-glucanases in other fungal species are discussed.
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Affiliation(s)
- T Fontaine
- Laboratoire des Aspergillus, Institut Pasteur, Paris, France.
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Abstract
Aspergillus nidulans conidiospores contain high levels of the non-reducing disaccharide trehalose. We show that upon induction of conidiospore germination, the trehalose pool is rapidly degraded and a glycerol pool is transiently accumulated. A trehalase with an acidic pH optimum was purified from conidiospores. Characterization of the treA gene encoding this trehalase shows that it is homologous to Saccharomyces cerevisiae vacuolar acid trehalase, the product of the ATH1 gene, and to two related proteins of unknown function identified in Mycobacterium tuberculosis and Mycobacterium leprae. A. nidulans mutants that lack acid trehalase activity were constructed by gene replacement at the treA locus. Analysis of these mutants suggests that the treA gene product is localized in the conidiospore wall, is required for growth on trehalose as a carbon source, and is not involved in the mobilization of the intracellular pool of trehalose. Therefore, it is proposed that a cytoplasmic regulatory trehalase is controlling this latter process.
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Affiliation(s)
- C d'Enfert
- Laboratoire des Aspergillus, Institut Pasteur, Paris, France.
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Affiliation(s)
- T Fontaine
- Aspergillus Laboratory, Pasteur Institute, Paris, France
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Fontaine T, Hartland RP, Beauvais A, Diaquin M, Latge JP. Purification and characterization of an endo-1,3-beta-glucanase from Aspergillus fumigatus. Eur J Biochem 1997; 243:315-21. [PMID: 9030754 DOI: 10.1111/j.1432-1033.1997.0315a.x] [Citation(s) in RCA: 67] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
An endo-1,3-beta-glucanase was purified from a cell wall autolysate of Aspergillus fumigatus. This beta-glucanase activity was associated with a glycosylated 74-kDa protein. Using a sensitive colorimetric assay and a high-performance anion-exchange chromatography with a pulsed electrochemical detector for product analysis, it was shown that the endoglucanase hydrolysed exclusively linear 1,3-beta-glucan chains, had an optimum pH of 7.0 and an optimum temperature of 60 degrees C. A substrate kinetic study gave a Km value of 0.3 mg/ml for soluble (laminarin and laminari-oligosaccharides) and 1.18 mg/ml for insoluble (curdlan) 1,3-beta-glucan. Laminari-oligosaccharide degradation, analysed by HPLC, showed that the endoglucanase bind to the subtrate at several positions and suggested that the active site of the enzyme recognized five glucose units linked by a 1,3-beta bond. The association of the present endo-1,3-beta-glucanase with the cell wall of A. fumigatus suggests a putative role for this enzyme during cell-wall morphogenesis.
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Affiliation(s)
- T Fontaine
- Institut Pasteur, Laboratoire des Aspergillus, Paris, France
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Hartland RP, Fontaine T, Debeaupuis JP, Simenel C, Delepierre M, Latgé JP. A novel beta-(1-3)-glucanosyltransferase from the cell wall of Aspergillus fumigatus. J Biol Chem 1996; 271:26843-9. [PMID: 8900166 DOI: 10.1074/jbc.271.43.26843] [Citation(s) in RCA: 92] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Cell wall transferases utilizing beta-(1-3)-glucan chains as substrates may play important roles in cell wall assembly and rearrangement, as beta-(1-3)-glucan is a major structural component of the cell wall of many fungi. A novel beta-(1-3)-glucanosyltransferase was purified to apparent homogenei ty from an autolysate of the cell wall of Aspergillus fumigatus. The enzyme had a molecular mass of 49 kDa and contained approximately 5 kDa of N-linked carbohydrate. The enzyme catalyzed an initial endo-type splitting of a beta-(1-3)-glucan molecule, followed by linkage of the newly generated reducing end to the nonreducing end of another beta-(1-3)-glucan molecule. Laminarioligosaccharides of size G10 and greater were donor substrates for the transferase. Laminarioligosaccharides of size G5 and greater formed acceptors. The enzyme was able to reuse initial transferase products as donors and acceptors in extended incubations, resulting in the formation of increasingly larger transferase products until they became insoluble. The major initial products from an incubation of the transferase with borohydride-reduced G11 (rG11) were rG6 and rG16. 1H NMR analysis of the rG16 transferase product showed it was a laminarioligosaccharide, indicating that the enzyme forms a beta-(1-3)-linkage during transfer. The enzyme may have a key function in vivo by allowing the integration of newly synthesized glucan into the wall and promoting cell wall expansion during cell growth.
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Affiliation(s)
- R P Hartland
- The Aspergillus Laboratory, Institut Pasteur, 25 rue du Docteur Roux, 75724 Paris Cedex 15, France
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Stephan MP, Fontaine T, Previato JO, Mendonça-Previato L. Differentiation of capsular polysaccharides from Acetobacter diazotrophicus strains isolated from sugarcane. Microbiol Immunol 1995; 39:237-42. [PMID: 7651237 DOI: 10.1111/j.1348-0421.1995.tb02195.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Capsular polysaccharides (CPSs) from six representative strains of Acetobacter diazotrophicus were isolated and fractionated by gel filtration and anion-exchange chromatography. Purified CPSs obtained in the non-adsorbed fraction of a DEAE-Sephadex A-25 column were qualitatively and quantitatively analyzed for sugar composition. Uronic acid and amino sugars were not detected in all purified CPSs. Basically the CPSs of A. diazotrophicus are composed of rhamnose, mannose, galactose and glucose. The presence of fucose was only observed in the CPS of strains PR2 and PAL3. Based on these results, the six strains of A. diazotrophicus could be divided into four groups according to the sugar content of their capsules: (i) fucose-containing capsules (PR2 and PAL3, localized in roots), (ii) mannose-rich capsule (PAL5, localized in root), (iii) capsules with a high ratio of hexose to rhamnose (PR4 and PR20, localized in stems) and (iv) capsules with a low ratio of hexose to rhamnose (PR14, localized in rhizosphere). For all CPSs, sodium dodecy sulfate-polyacrylamide gel electrophoresis showed diffuse bands of slow mobility in silver-stained gels. The different CPS migration patterns could not be correlated with sugar composition. The purified CPS of strain PAL3 was found to be immunogenic and immunochemically similar to the CPS of strain PR2. The serological specificity to CPS of strains PAL3 and PR2 correlated well with the presence of focuse, indicating that this deoxyhexose is immunodominant.(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- M P Stephan
- Laboratory of Biochemistry, National Centre of Research on Agrobiology-EMBRAPA/CNPAB-Rio de Janeiro-Brazil
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Maddelein ML, Libessart N, Bellanger F, Delrue B, D'Hulst C, Van den Koornhuyse N, Fontaine T, Wieruszeski JM, Decq A, Ball S. Toward an understanding of the biogenesis of the starch granule. Determination of granule-bound and soluble starch synthase functions in amylopectin synthesis. J Biol Chem 1994; 269:25150-7. [PMID: 7929203] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
Plant starch synthesis can be distinguished from those of bacterial, fungal, and animal glycogen by the presence of multiple elongation (starch synthases) and branching enzymes. This complexity has precluded genetic assignment of functions to the various soluble starch synthases in the building of amylopectin. In Chlamydomonas, we have recently shown that defects in the major soluble starch synthase lead to a specific decrease in the amount of a subset of amylopectin chains whose length ranges between 8 and 40 glucose residues (Fontaine, T., D'Hulst, C., Maddelein, M.-L., Routier, F., Marianne-Pepin, T., Decq, A., Wieruszeski, J. M., Delrue, B., Van Den Koornhuyse, N., Bossu, J.-P., Fournet, B., and Ball, S. G. (1993) J. Biol. Chem. 268, 16223-16230). We now demonstrate that granule-bound starch synthase, the enzyme that was thought to be solely responsible for amylose synthesis, is involved in amylopectin synthesis. Disruption of the Chlamydomonas granule-bound starch synthase structural gene establishes that synthesis of long chains by this enzyme can become an absolute requirement for amylopectin synthesis in particular mutant backgrounds. In the sole presence of soluble starch synthase I, Chlamydomonas directs the synthesis of a major water-soluble polysaccharide fraction and minute amounts of a new type of highly branched granular material, whose structure is intermediate between those of glycogen and amylopectin. These results lead us to propose that the nature of the elongation enzyme conditions the synthesis of distinct size classes of glucans in all starch fractions.
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Affiliation(s)
- M L Maddelein
- Laboratoire de Chimie Biologique, Unité Mixte de Recherche du CNRS 111, Université des Sciences et Technologies de Lille, Villeneuve d'Ascq, France
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Maddelein M, Libessart N, Bellanger F, Delrue B, D'Hulst C, Van den Koornhuyse N, Fontaine T, Wieruszeski J, Decq A, Ball S. Toward an understanding of the biogenesis of the starch granule. Determination of granule-bound and soluble starch synthase functions in amylopectin synthesis. J Biol Chem 1994. [DOI: 10.1016/s0021-9258(17)31510-7] [Citation(s) in RCA: 84] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
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Fontaine T, D'Hulst C, Maddelein ML, Routier F, Pépin TM, Decq A, Wieruszeski JM, Delrue B, Van den Koornhuyse N, Bossu JP. Toward an understanding of the biogenesis of the starch granule. Evidence that Chlamydomonas soluble starch synthase II controls the synthesis of intermediate size glucans of amylopectin. J Biol Chem 1993; 268:16223-30. [PMID: 8344907] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
Low starch mutants of Chlamydomonas reinhardtii were isolated after x-ray mutagenesis of wild-type strain 137C. The mutants accumulated 20-40% of the normal amount and displayed a 2-fold decrease of the total glycogen-primed soluble starch synthase activity. Three different mutant alleles of the st-3 gene were isolated that were characterized by similar defects and displayed a net increase in amylose content. Amylose-primed synthesis of glucan in native gels revealed a complete wipe out of one of the soluble starch synthases. Zymograms and kinetic analyses performed both in the mutant and in partially purified wild type extracts reveal at least two distinct activities that are partly analogous to higher plant soluble starch synthases I and II (SSI and II). The st-3 mutants were defective for SSII. Methylation and debranching of the purified amylopectin fraction clearly show a decrease in the number of intermediate size glucans (dp8 to 50) and an absolute and relative increase of very short glucans (dp2 to 7). These results suggest that a soluble starch synthase may be necessary for the synthesis or maintenance of intermediate size glucans that are the main component of the branched clusters of amylopectin.
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Affiliation(s)
- T Fontaine
- Laboratoire de Chimie Biologique, Université des Sciences et Technologies de Lille Flandres-Artois, Villeneuve, d'Ascq, France
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Fontaine T, D'Hulst C, Maddelein M, Routier F, Pépin T, Decq A, Wieruszeski J, Delrue B, Van den Koornhuyse N, Bossu J. Toward an understanding of the biogenesis of the starch granule. Evidence that Chlamydomonas soluble starch synthase II controls the synthesis of intermediate size glucans of amylopectin. J Biol Chem 1993. [DOI: 10.1016/s0021-9258(19)85409-1] [Citation(s) in RCA: 93] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
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Abstract
The hemicelluloses extracted from sunflower hulls by repeated alternating oxidative and alkaline treatments were purified by precipitation with Cetavlon and then ion-exchange chromatography on DEAE-trisacryl. The resulting fractions were examined by hydrolysis, methylation, GLC-MS, and NMR spectroscopy. The hemicelluloses are of the glucuronoxylan type with the following structure -->4)-beta-D-Xylp-(1-->4)-[4-O-Me-alpha-D-GlcpA-(1-->2)]-bet a-D-Xylp-(1-->. The polysaccharides differed in the amount of branching; the ratio of the main fraction 4-O-MeGlcA:Xyl was 1:8-9.
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Affiliation(s)
- A Bazus
- Laboratoire de Chimie des Agroressources, Ecole Nationale Supérieure de Chimie de Toulouse, France
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Delrue B, Fontaine T, Routier F, Decq A, Wieruszeski JM, Van Den Koornhuyse N, Maddelein ML, Fournet B, Ball S. Waxy Chlamydomonas reinhardtii: monocellular algal mutants defective in amylose biosynthesis and granule-bound starch synthase activity accumulate a structurally modified amylopectin. J Bacteriol 1992; 174:3612-20. [PMID: 1592815 PMCID: PMC206049 DOI: 10.1128/jb.174.11.3612-3620.1992] [Citation(s) in RCA: 144] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Amylose-defective mutants were selected after UV mutagenesis of Chlamydomonas reinhardtii cells. Two recessive nuclear alleles of the ST-2 gene led to the disappearance not only of amylose but also of a fraction of the amylopectin. Granule-bound starch synthase activities were markedly reduced in strains carrying either st-2-1 or st-2-2, as is the case for amylose-deficient (waxy) endosperm mutants of higher plants. The main 76-kDa protein associated with the starch granule was either missing or greatly diminished in both mutants, while st-2-1-carrying strains displayed a novel 56-kDa major protein. Methylation and nuclear magnetic resonance analysis of wild-type algal storage polysaccharide revealed a structure identical to that of higher-plant starch, while amylose-defective mutants retained a modified amylopectin fraction. We thus propose that the waxy gene product conditions not only the synthesis of amylose from endosperm storage tissue in higher-plant amyloplasts but also that of amylose and a fraction of amylopectin in all starch-accumulating plastids. The nature of the ST-2 (waxy) gene product with respect to the granule-bound starch synthase activities is discussed.
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Affiliation(s)
- B Delrue
- Laboratoire de Chimie Biologique, Université des Sciences et Techniques de Lille Flandres-Artois 59655, Villeneuve d'Ascq, France
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Fontaine T, Talmont F, Dutton GG, Fournet B. Analysis of pyruvic acid acetal containing polysaccharides by methanolysis and reductive cleavage methods. Anal Biochem 1991; 199:154-61. [PMID: 1812780 DOI: 10.1016/0003-2697(91)90083-6] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The mass spectra of permethylated methyl 4,6-O-(1-carbomethoxyethylidene)-D-hexopyranoside and 1,5-anhydro-D-hexitol of glucose, galactose, and mannose and permethylated methyl 5,6-O-(1-carbomethoxyethylidene)-D-galactofuranoside and 1,4-anhydro-D-galactitol have been determined. The stability of each compound toward methanolysis and reductive cleavage is discussed. These techniques permit the identification of the acetalic linkages of pyruvic acid present in polysaccharides.
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Affiliation(s)
- T Fontaine
- Laboratoire de Chimie Biologique, Université des Sciences et Techniques de Lille Flandres-Artois, Villeneuve d'Ascq, France
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Talmont F, Vincent P, Fontaine T, Guezennec J, Prieur D, Aymard P, Cuvelier G, Launay B, Fournet B. Structural investigation of an acidic polysaccharide from a deep-sea hydrothermal vent marine bacterium. Food Hydrocoll 1991. [DOI: 10.1016/s0268-005x(09)80307-x] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Fontaine T, Wieruszeski JM, Talmont F, Saniez MH, Duflot P, Leleu JB, Fournet B. Exopolysaccharide structure from Bacillus circulans. Eur J Biochem 1991; 196:107-13. [PMID: 2001692 DOI: 10.1111/j.1432-1033.1991.tb15792.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Affiliation(s)
- T Fontaine
- Laboratoire de Chimie Biologique et Unité Mixte de Recherche du CNRS n.111, Université des Sciences et Techniques de Lille Flandres-Artois, France
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